JPH0113879B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the state of drainage from the washing tub in a two-tub washing machine or the washing/dehydration tub in a single-tub washing machine based on a change in light transmittance. The present invention relates to a method for detecting the completion of draining in an automatic washing machine, in which the draining process is terminated based on a change in the amount of water.

Conventionally, the drain time of a washing machine was set mechanically by a time switch, and this time was set regardless of the amount of rinse water, wash water, or even cloth during rinsing or washing. .
As a result, even if there is no water left in the washing tub or washing/spinner tub, the drain valve may still be open and the drain valve will not move on to the next process, which is the spin process, resulting in wasted time. It was a passing thing. or,
The electromagnetic valve used to open the drain valve is also constantly operating during draining, resulting in wasted power consumption, which is uneconomical.

The present invention solves the above-mentioned conventional problems, and one embodiment thereof will be described below based on the accompanying drawings.

In FIG. 1, 1 is the main body of the washing machine, and 2 is an outer tub, which is suspended and supported from the four corners of the main body 1 by rods 3. Reference numeral 4 denotes an inner tank which is a washing and dehydrating tank having a large number of holes 4a in the wall surface, and has a rotary blade 5 rotatably in the center of the bottom.

Reference numeral 6 is a mechanism part which is provided at the bottom of the outer tank 2 and has a brake/clutch mechanism inside; 7 is a motor which rotates the rotor blade 5 through the mechanism part 6 during washing and rinsing; The inner tank 4 is rotated for dehydration.

8 is a drainage pot, which is composed of a valve part, an inflow pipe, and an outflow pipe. The inflow pipe is the outer tank 2
The outflow pipe is connected to a drain hose 9 to the outside of the machine. Reference numeral 10 denotes a detection unit for detecting the end time of drainage, in which a light-emitting element and a light-receiving element for detecting the transmittance of light through the drainage liquid are provided facing each other.

FIG. 2 shows the operation of the detection unit 10 in the draining process c after the washing process a and after the rinsing process b. This is the converted version. An electrical circuit as shown in FIG. 3 is used so that when the light transmittance decreases, the output voltage of the light receiving element increases. In FIG. 3, 11 is a light emitting element, 12 is a light receiving element, 13, 14 and 15 are resistors, and 16 is a capacitor.

In FIG. 2, characteristic A shows the change in output voltage during the draining process after washing, and characteristic B shows the change in the output voltage during the draining process after rinsing. d is the dehydration process.

In the above configuration, the valve part of the drain pot 8 is closed during the washing process and the rinsing process.
Washing water and rinsing water fill the inlet pipes of the outer tank 2 and the drain tank 8. When the washing or rinsing process is completed and the next draining process begins, the valve of the drain pot 8 is opened by the suction force generated by energizing a solenoid (not shown). Then, the washing water or rinsing water is drained through the inlet pipe and the drain hose 9.

When the valve part of the drain pot 8 is opened, the inner tank 4
And the bubbles generated in the outer tank 2 flow into the inflow pipe, the transmittance of the detection part 10 decreases, and the output voltage rapidly increases.
Furthermore, as drainage continues, the output voltage gradually decreases. When the washing water or rinsing water runs out in the outer tank 2, a break is created in the water that had been flowing filling the inflow pipe, and air enters the inflow pipe.
The light from the light emitting element 11 of the detection unit 10 is diffusely reflected and the transmittance is extremely reduced. At this time, the light receiving element 12
The output voltage of will increase rapidly. Therefore, by detecting this point, it is detected that there is no washing liquid or rinsing liquid in the outer tub 2, that is, the end of drainage is detected. That is, first, after a certain period of time, for example 10 to 30 seconds, has elapsed since the start of the drainage process, the permeability is detected over time, that is, continuously or at regular intervals. Then, the draining process is terminated by detecting the point t in FIG. 2 where the transmittance suddenly changes, that is, the point where the output voltage suddenly increases. At the increase point, the output voltage increases by 0.1-0.5V per second.
Note that the reason why the permeability is detected after a certain period of time has elapsed from the start of drainage is to avoid erroneously detecting the increased portion of the output voltage at the beginning of the drainage process as the time t when the drainage ends.

As described above, according to the present invention, the transmittance of light through the draining liquid is detected over time after a certain period of time has elapsed from the start of the draining process, and the rapid change in transmittance that occurs at the end of the draining process (inflow pipe This system detects air (which occurs when air enters the gaps in the water and diffusely reflects or refracts the light from the light emitting element) and stops the drainage process. Therefore, the characteristic change of the detection part is large, and it can be detected with high precision, and it is possible to quickly detect when the drainage liquid has run out without being affected by water droplets or residual water, which are not a practical problem, and to indicate the completion of drainage. Therefore, the draining process can be carried out at a draining time that corresponds to the amount of water used during washing or rinsing, leading to a shorter washing cycle. Furthermore, the time required to energize a means for opening a drainage path, such as a solenoid for operating a valve, can be shortened, and electric power can be saved.

[Brief explanation of drawings]

Fig. 1 is a schematic vertical cross-sectional view of an automatic washing machine according to an embodiment of the present invention, Fig. 2 is a diagram showing the characteristics when the change in transmittance during the drainage process is regarded as a change in the output of the light receiving element, and Fig. 3 is an electrical circuit diagram of the detection section. 10...Detection unit, 11...Light emitting element, 12...
Light receiving element.

Claims (1)

[Claims] 1. In order to detect changes in the transmittance of light through the drainage liquid in the inflow pipe, a detection section consisting of a light emitting element and a light receiving element facing each other is installed near the drainage pot, and after a certain period of time has elapsed from the start of the drainage process. , an automatic washing machine characterized by detecting a sudden change in transmittance caused by diffused reflection or refraction of light from a light emitting element due to air intrusion occurring in the cut in the water in the detection section, and stopping the draining process. A method for detecting the end of drainage.